OPTICAL PICKUP DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup device capable of recording and reproducing data on/from different types of optical media by using three different wavelengths.

SOLUTION: This optical pickup device is provided with a first light source 12 of a wavelength λ1 for recording/reproducing information on/from a second optical medium of a transparent substrate with a thickness of t1; a second light source 11 of a wavelength λ2 (λ1 < λ2) for recording/reproducing information on/from a first optical medium of the transparent substrate with the thickness of t1; a third light source 13 of a wavelength λ3 (λ2 < λ3) for recording/reproducing information on/from a third optical medium of a transparent substrate with a thickness of t2 larger than t1; a common objective lens 1 for converging luminous flux from the first light source 12 on the information recording surface of the second optical medium in recording/reproducing the information on/from the second optical medium, converging luminous flux from the second light source 11 on the information recording surface of the first optical medium in recording/reproducing the information on/from the first optical medium and converging luminous flux from the third light source on the information recording surface of the third optical medium in recording/reproducing the information on/from the third optical medium. The device is further provided with a photodetector 30 for receiving reflected light modulated by each of the information recording surfaces.

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